1. Field of the Invention
The present invention relates to adjustable beds used for nursing care, apnea syndrome treatment, and the like. In particular, the invention relates to improvements in control of operations of turning a cared-for person who is lying in bed during his or her sleep.
2. Related Art
To prevent the user such as a cared-for person from developing decubitus ulcers (i.e. bedsores), a typical adjustable bed used as a turn assisting bed tilts one part of or the entire surface of the mattress on which the user is lying, to assist the user to turn in the tilt direction and thereby change his or her position. Such an adjustable bed employs a mechanism of tilting the mattress from a horizontal position toward one of the left and right sides (in a lateral direction) (see Unexamined Japanese Patent Application Publication No. H06-14824 as one example).
Conventionally, timings with which the user is turned in his or her sleep are controlled by setting a timer before the user falls asleep so as to automatically tilt the mattress at, for example, two-hour intervals.
According to this conventional method of mechanically setting turn timings using a timer, however, there may be a possibility that the user is forced to turn even when his or her body does not really need such an action. This causes the user to suffer mental stress unknowingly, as a result of which his or her sleep may be disturbed.